[SDL] SDL 2D Camera - 2D 카메라

SDL에 2D 카메라를 만들어 보자.

 

character.bmp

0.00MB

shop.bmp

0.03MB

 

 

#include "SDL.h"
 
class Camera {
public:
    int m_width;
    int m_height;
    int m_cameraBorder;
    int m_target_width;
    int m_target_height;
    float m_x, m_y;
    SDL_Texture* m_targetTexture;
public:
    Camera(SDL_Renderer* renderer, int width, int height, int border, SDL_BlendMode mode) {
        m_width = width;
        m_height = height;
        m_cameraBorder = border;
        m_target_width = width + border * 2;
        m_target_height = height + border * 2;
        m_x = 0;
        m_y = 0;
        m_targetTexture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_TARGET,
            m_target_width, m_target_height);
        SDL_SetTextureBlendMode(m_targetTexture, mode);
    }
    void Draw(SDL_Renderer* renderer, int windowHeight) {
        float pixel_h = (float)windowHeight / m_height;
        float correction_x = (int)m_x - m_x;
        float correction_y = (int)m_y - m_y;
        SDL_Rect dst = { (int)(correction_x * pixel_h - pixel_h * m_cameraBorder),
            (int)(correction_y * pixel_h - pixel_h * m_cameraBorder),
            (int)(m_target_width * pixel_h),
            (int)(m_target_height * pixel_h) };
        SDL_RenderCopy(renderer, m_targetTexture, NULL, &dst);
    }
    void Update(int xDirection, int yDirection) {
        m_x += 0.5f * xDirection;
        m_y += 0.5f * yDirection;
    }
    void CameraReset(SDL_Renderer* renderer, int width, int height, int border, SDL_BlendMode mode) {
        m_width = width;
        m_height = height;
        m_cameraBorder = border;
        m_target_width = width + border * 2;
        m_target_height = height + border * 2;
        SDL_DestroyTexture(m_targetTexture);
        m_targetTexture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA32, SDL_TEXTUREACCESS_TARGET,
            m_target_width, m_target_height);
        SDL_SetTextureBlendMode(m_targetTexture, mode);
    }
    ~Camera() {
        SDL_DestroyTexture(m_targetTexture);
    }
};
 
class Sprite {
public:
    int width;
    int height;
    float m_destX, m_destY;
    SDL_Surface* surface;
    SDL_Texture* texture;
public:
    Sprite(SDL_Renderer* renderer, const char* filename) {
        surface = SDL_LoadBMP(filename);
        width = surface->w;
        height = surface->h;
        m_destX = 0;
        m_destY = 0;
        texture = SDL_CreateTextureFromSurface(renderer, surface);
        SDL_FreeSurface(surface);
    }
    void DrawSprite(SDL_Renderer* renderer, Camera* camera, int x, int y) {
        SDL_Rect destRect = { (int)(m_destX - camera->m_x) + camera->m_cameraBorder + x,
                (int)(m_destY - camera->m_y) + camera->m_cameraBorder + y,
                width, height };
 
        SDL_RenderCopy(renderer, texture, NULL, &destRect);
    }
    ~Sprite() {
        SDL_DestroyTexture(texture);
    }
};
 
int main(int argc, char** argv) {
    const int Window_Width = 640;
    const int Window_Height = 480;
 
    SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
    SDL_Window* window = SDL_CreateWindow("SDL Simple Camera", SDL_WINDOWPOS_CENTERED,
        SDL_WINDOWPOS_CENTERED, Window_Width, Window_Height, SDL_WINDOW_RESIZABLE);
    SDL_assert(window);
 
    SDL_SetHint(SDL_HINT_RENDER_BATCHING, "1");
    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED |
        SDL_RENDERER_PRESENTVSYNC);
    SDL_assert(renderer);
 
    // Init
    Camera camera = Camera(renderer, 160, 120, 1, SDL_BLENDMODE_BLEND);
    SDL_assert(camera.m_targetTexture);
    Sprite shopSprite = Sprite(renderer, "shop.bmp");
    Sprite characterSprite = Sprite(renderer, "character.bmp");
 
    int xDirection = 0;
    int yDirection = 0;
 
    SDL_Event event;
    bool quit = false;
 
    while (!quit) {
        while (SDL_PollEvent(&event)) {
            switch (event.type) {
            case SDL_QUIT:
                quit = true;
                break;
            case SDL_KEYDOWN:
                if (event.key.keysym.sym == SDLK_ESCAPE)
                    quit = true;
                if (event.key.keysym.sym == SDLK_LEFT)
                    xDirection = -1;
                if (event.key.keysym.sym == SDLK_RIGHT)
                    xDirection = 1;
                if (event.key.keysym.sym == SDLK_UP)
                    yDirection = -1;
                if (event.key.keysym.sym == SDLK_DOWN)
                    yDirection = 1;
                if (event.key.keysym.sym == SDLK_r)
                    camera.CameraReset(renderer, 160, 120, 1, SDL_BLENDMODE_BLEND);
                if (event.key.keysym.sym == SDLK_e)
                    camera.CameraReset(renderer, 640, 480, 1, SDL_BLENDMODE_BLEND);
                break;
 
            default:
                xDirection = 0;
                yDirection = 0;
                break;
            }
        }
        camera.Update(xDirection, yDirection);
 
        // Camera target
        SDL_SetRenderTarget(renderer, camera.m_targetTexture);
        SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0xFF);
        SDL_RenderClear(renderer);
 
        // Draw Sprite
        shopSprite.DrawSprite(renderer, &camera, 0, 0);
        characterSprite.DrawSprite(renderer, &camera, 116, 66);
 
        // Screen target
        SDL_SetRenderTarget(renderer, NULL);
        SDL_SetRenderDrawColor(renderer, 0x00, 0xFF, 0x00, 0xFF);
        SDL_RenderClear(renderer);
 
        camera.Draw(renderer, Window_Height);
 
        SDL_RenderPresent(renderer);
    }
 
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
 
    return 0;
}

 

코드를 입력하고 빌드한다.

 

실행하면 shop과 character 스프라이트가 표시된다.

 

r, e 키로 해상도를 바꿀 수 있다.

 

방향키로 카메라를 움직일 수 있다.

 

 

※ 참고

Pixel perfect camera in SDL2